Valid Pop token format

[K1li4nL]

For now the form a valid PoP token must have is undefined. For example, the scala backend will consider any base64 strings to be acceptable pop tokens, including empty ones, leading to issues when creating channels for rollcall participants... Another example is Fe1 that doesn't even have the requirement of them being base64 when scanning tokens during rollcall. There is a need to agree on the format (i.e: regex) valid pop token should have so as to avoid as much as possible undefined behaviours among subsystems.

Subsystems concerned:

Front-ends:

• [ ] Fe1-Web (please include browser's names & version)
• [ ] Fe2-Android (please specify if phone or emulation, and Android version)

Back-ends:

• [ ] Be1-Go
• [ ] Be2-Scala

[Tyratox]

See https://github.com/dedis/popstellar/blob/master/protocol/qrcode/pop_token.json

[osm-alt]

I see that all tasks have been marked as done. Should this issue be closed?

[K1li4nL]

My bad, the way I put it is confusing (I initially selected all the systems as a way to show they were all concerned, edited now). Given that the pop token is still defined as a format-less string I wouldn't say this issues is solved (unless it is decided things are good enough this way)